Are you ready to leave your corporate career behind to find work at a nonprofit? I applaud you. But I also have a warning: If you don’t take the time to learn about the unique needs, expectations and culture of the nonprofit sector before you send out your resumé, you might run into unexpected roadblocks that will keep you from getting hired.

These days, more and more Americans are shifting to nonprofit work after spending decades in the business world. As many as 9 million people age 44 to 70 have begun “encore careers” that combine social purpose with pay, and an additional 31 million hope to join them, according to a 2011 survey by Encore.org, the nonprofit think tank.

But as a career coach I’ve learned that making the transition from the corporate world to the nonprofit world doesn’t always happen as easily or as quickly as you might expect.

So to help you make the move, I’ve put together five mistakes to avoid when looking for work at a nonprofit:

1. Applying at a nonprofit because you want an easy job. Many people have the misperception that working at a nonprofit will require less effort than a for-profit enterprise. But the opposite is true.

“When you work at a nonprofit, you’re surrounded by people driven by a sense of mission and they operate at a very, very different RPM level” than corporate employees, says Wayne Luke, a partner at the Bridgespan Group, a nonprofit adviser based in Boston.

Jan Brown, a career coach and board chair of Powwow, a New York-based networking group for women at nonprofits, agrees. “You may still work weekends or put in 12-hour days," she warns. "There just won’t be car service waiting to take you home at the end of the night.”

So apply for a job at a nonprofit because you support its mission, not because you see it as an easy way to glide into the sunset after your corporate career.

2. Looking for a paid position at a nonprofit without ever volunteering. Hiring managers at nonprofits are suspicious of candidates who profess they care about the group’s mission, or even about helping others generally, but have no experience to back up their claims.

“Saying you are passionate about hunger issues and then having zero volunteer experience in that area will not go unnoticed,” Brown says.

Be sure to devote time and energy as a volunteer to an organization whose purpose matters to you before launching a search for a paid nonprofit job.

3. Assuming that nonprofits aren’t run like real businesses. Sure, nonprofits are focused on their missions. But they still want people who can help manage operations, cut costs and raise pots of money.

Nonprofits these days are especially keen on hiring applicants with strong management and financial skills, since the challenging economic times are forcing groups to compete for fewer dollars.

When you go for an interview, be prepared to demonstrate how you can effectively and efficiently help the nonprofit maximize its money and resources.

4. Being arrogant about your for-profit experience during the interview. Yes, your business background can help make you an attractive candidate. But don’t be fooled into thinking that attractive equals superior.

“Assuming your successes in the corporate world were harder to achieve than if you’d been at a nonprofit, or that your expertise is somehow weightier, is just not true,” Brown cautions. “Many of the people who work in the nonprofit world are professionals with solid experience who have worked their way up, gathering valuable and relevant expertise along the way.”

When discussing your accomplishments during an interview, explain how you could ensure comparable success within the culture and restrictions of the nonprofit sector.

5. Neglecting to display your kinder qualities during the interview. Although it’s important to appear serious and bottom-line focused, the nonprofit interviewer will also want to get a sense that you would be a team player and consensus builder. That’s because employees in this world must often work with diverse populations and volunteer staffers.

Be prepared to demonstrate that you know how to play nicely in many different types of sandboxes and that you’ve done so impressively. That just might get you a bucket, a shovel and a paycheck.